Influence of Graphene Curvature on Hydrogen Adsorption: Toward Hydrogen Storage Devices

Abstract

2The ability of atomic hydrogen to chemisorb on graphene makes the latter a promising material for hydrogen storage. Based on scanning tunneling microscopy techniques, we report on site-selective adsorption of atomic hydrogen on convexly curved regions of monolayer graphene grown on SiC(0001).This system exhibits an intrinsic curvature owing to the interaction with the substrate. We show that at low coverage hydrogen is found on convex areas of the graphene lattice. No hydrogen is detected on concave regions. These findings are in agreement with theoretical models which suggest that both binding energy and adsorption barrier can be tuned by controlling the local curvature of the graphene lattice. This curvature-dependence combined with the known graphene flexibility may be exploited for storage and controlled release of hydrogen at room temperature making it a valuable candidate for the implementation of hydrogen-storage devices.

Measurement of topological Berry phase in highly disordered graphene

“…After introducing CVD graphene samples into the UHV chamber, they were annealed at 673 K for 2 hours in order to remove water and other adsorbates. At this temperature, it was observed that hydrogen does not desorb from similar samples of graphene on silicon carbide 22 . The temperature was measured by a type K thermocouple at the position of the sample and cross-calibrated by an optical pyrometer.…”

“…Angle resolved photo-emission spectroscopy (ARPES) and photocurrent measurements give evidence for the onset of insulating electron transport behaviour at H/C≈ 0.1% 15 , with higher hydrogen coverage giving clear evidence of gap formation and the presence of mid-gap states 19,20 . STM imaging 21,22 has mapped the local density of states in the vicinity of both lone hydrogen adsorbates and hydrogen adsorbate pairs. Previous magnetotransport measurements show that the ν = 2 QHE state can be observed in hydrogenated graphene 16 , as well as in disordered graphene grown by sublimation of SiC 17,18 .…”

Complete Modeling of the Hydrogen Stored in a Spherical Cavity

“…Hydrogen energies are quantified by the two parameters ν and ℓ, these energies depends on the self-adjoint extension parameter (as possible) which identify the materiel properties of the inner cavity wall, many scientists consider the cavity envelopes made with nanotechnology, fibers and polymers, [6][7][8][9][10][11][12][13][14]. The energies of the hydrogen are also a function of the radius of the spherical cavity.…”

Directed growth of hydrogen lines on graphene: High-throughput simulations powered by evolutionary algorithm

“…It is well known that curvature enhances chemical reactivity of graphene and related materials by decreasing the activation barrier for adsorbates [15][16][17][18][19][20][21][22]. This property was used to enhance the hydrogen storage capacity of graphene and CNTs [23][24][25][26][27]. A straightforward way to deform graphene is to introduce steps in the underlying substrate.…”